Sheet feeding mechanism



Feb.'25, 1958 A. BUTTNER ,3

SHEET FEEDING MECHANISM Filed May a, 1955 2'; Sheets-Sheet 1 INVENTOR Arfur B12 fiver ATmm/EY Feb. 25, 1958 A BUTTNER 2,824,738 SHEET FEEDING MECHANISM Filed May 5, 1955 5 Sheets-Sheet 2 LP w figj '7 7 6 w H-H -r I I "P y? INVENTOR: Arm BAH/v6 A TTORNE? Feb. 25, 1958 A. BUTTNER 2,824,738

SHEET FEEDING MECHANISM Filed May 3, 1955- 3 Sheets-Sheet 3 lNVENTOP Arfur Bbiff 6% ATTORNEY United States Patent SHEET FEEDING MECHANISM Artur Biittner, Heidelberg, Germany, assignor to Schnellpressenfabrik Aktiengesellschaft Heidelberg, Heidelberg, Germany, a corporation of Germany Application May 3, 1955, Serial No. 505,761

Claims priority, application Germany May 7, 1954 1 Claim. (Cl. 271-62) The present invention relates to mechanism for feeding sheets of material from a stack. As the invention is particularly applicable to feeding sheets of paper to a printing press, it will be described in conjunction with an embodiment for that purpose, but it will be understood that the invention is likewise applicable to other sheet-feeding devices.

The invention relates to sheet-feeding mechanism of the kind in which a stack of sheets is supported by a vertically movable table. As the sheets are removed one after another from the top of the stack by suitable vacuum or other mechanism, the table supporting the stack is moved progressively upwardly so as to keep the top of the stack at a substantially constant level. When one stack of sheets is exhausted, a new stack must be supplied. In order to save change-over time, it is desirable to have a new stack of sheets pre-formed so that it can be quickly andeasily made available to the sheet-feeding mechanism.

In accordance with the present invention, the sheetfeeding mechanism is provided with a plurality of like tables for supporting stacks of sheets. One of such tables is supported by a pair of opposite spaced carriers which are movable vertically, for example by means of racks and pinions, threaded spindles and nuts or the like. The table is connected to the carriers in an easily detachable manner by coupling means operable either automatically or by hand, such as latch bolts or catches. When a table supported by the carriers approaches the limit of its upward movement, i. e. when the stack of sheets on it is nearly depleted, a second table carrying a new stack of sheets is positioned in the empty space directly beneath the first mentioned table. When .the first table becomes empty, it is" removed from the carriers, quick removal being permitted by the connecting means which is of the quick-disconnect type. The carriers are thereupon lowered to the level of the second table which is quickly connected to the carriers in like manner. Sheets are then fed from the stack on the second table which is raised progressively by the carriers so as to keep the topof the stack at the same level. Successive stacks of sheets are introduced into the machine one after another in like manner, the cycle of operations being repeated; By thus pre-stacking the sheets andiby provi'dihg'for the quick replacement of an empty tablewith a full one, loss of time is avoided and the productive operating time of the machine is increased.

The nature, objects and advantages of the invention will be more fully understood from the following description and claim in conjunction with the accompanying drawings in which:

Fig. l is a side elevation of a portion of sheet-feeding mechanism in accordance with the invention, the mechanism being shown with a feeding stack in use and a prepared stack in position for use when the first stack is exhausted.

Fig. 2 is a rear view of the mechanism shown in Fig. 1.

"ice Fig. 3 is a view similar to Fig. 2 but with the upper feed table removed.

Fig. 4 is a view similar to Fig. 3 but with the table carriers lowered to engage the second table. I

Fig. 5 is an enlarged fragmentary section taken on the line VV in Fig. 1, but with the carriers in their lower position.

Fig. 6 is a partial plan view of 'a table support and locking mechanism.

Fig. 7 is a fragmentary sectional view taken approximately on the line VII-VII in Fig. 6, the locking mechanism being shown in released position.

Fig. 8 is a fragmentary section similar to Fig. 7 but wit-h the locking mechanism shown in locked position.

The sheet-feeding mechanism illustrated by way of example in the drawings has side frame portions 1 which may be part of, or attached to, the frame of a printing press or other machine to which the sheets are to be fed. A stack of sheets 2 is supported by a vertically movable table 3, the table being shown near its upper position with only a small quantity of sheets remaining in the residual stack 2. The sheets of paper, or other material, are successively removed from the top of the stack 2 in known manner, for example by a suction tube 4, and are fed to the operation in which they are used. The feeding stack is guided in the usual way by means of front stops 5 which are fixed between the side walls 1 of the sheet-feeding mechanism and side stops 6 which are displaceably mounted on the table 3. The table 3' is supported by a pair of opposite spaced carriers 7 which are fixed respectively on the upper end portions of a pair of toothed racks 8 which extend vertically and are guided by suitable bearing portions of the machine frame for movement in a vertical direction. The raising and lowering of the carriers 7 and of the table 3 supported by them is effected by means 'of pinion's 9 which engage the racks 8 and are fixed on a shaft 10 extending trans-' versely of the machine; The shaft 10 is rotatable by a drive and control mechanism 10a in known manner so as to raise the table 3 progressively as sheets are ported by two carrier rails 11 which are carried by theframe of the machine and permit the table 3a bearing a stack of sheets 2a tobe slid easily into position beneath the table 3 when the latter is in raised position. The two :feed tables 3 and 3a are identical with one another and thus interchangeable. Still additional feed tables may be provided, if desired, so that additional stacks of sheets may be prepared in advance.

The connections between the table "3' and the opposite carriers 7 are of the quick-disconnect type. In the embodiment illustrated in the drawings, each of the carriers 7 is provided with two latch bolts 12 which extend transversely of the carriers and are movable be tween a retracted position and an operative position in which they project from the carriers so as to engage a table 3a disposed between the opposite carriers 7, as illustrated in Fig. 5. Each of the latch bolts 12 is biased toward its operative position by a coil spring 13 which surrounds the bolt and acts between an annular shoulder 13a of the carrier 7 and an annular shoulder 13b on the bolt. A collar 14 fixed to the outer end of the bolt by a set screw or pin 14a limits the inward movement of the bolt. The projecting inner ends of the bolt have straight upper faces 15 on which the table 3 or 3a rests and inclined or wedge-shaped lower faces 15a.""..";

In addition to the spring latches 12, one or both of the carriers 7 are provided with quickly operable locking devices for positively locking a table in place between thecarriers. As illustrated more particularly in Figs. 6; '7 and 8, the locking device comprises a pin 16 which is longitudinally displaceable in a suitable hole provided in the carrier 7 between a retracted position (Fig. 7) and a projected or locked position (Fig. 8) in which a reduced portion 16a of the pin engages in a corresponding hole 17 of the feed table. The locking pin 16 is displaceable by a shaft 20 which is rotatably 1 mountedin the table carrier 7 and is provided at its inner end with an eccentric peg 19 engaging in a transverse slot 18 in the pin 16. On its free front end, the shaft 20 carries a handle 21 (Fig. 6) by means of which the shaft is rotatable through 180 to shift the pin 16 between its locked and released positions.

The operation of the mechanism is as follows: During use' of the stack 2, the feed table 3 is progressively raised by the carriers 7, racks 8, pinions 9 and the control mechanism 10a so as to keep the top of the stack 2 at a constant level. When the table 3 approaches the upper limit of its movement, the stack 2 being almost used up, a second table 3a is pushed in underneath the table 3 on the carrier rails 11. The second table 3a supports a fresh stack of sheets 2a which may be stacked on the table either before or after it is inserted, the stack being guided and kept vertical by the front stops and the side stops 6a. As soon as the last sheet of the stack 2 is used up, the locking mechanism is released by turning the handle 21 and the empty table 3 is removed from the supporting latch bolts 12. The racks 8,together with the carriers 7, are then lowered from the position shown in Fig. 3 to that shown in Fig. 4, for example by turning the crank b. During the end portion of this lowering movement, the inclined lower surfaces a of the springpressed latch bolts 12 engage the edges of the table 3a supported by the rails 11 and the bolts are thereby pressed outwardly against the action of springs 13 to permit the carriers 7 to move to the position shown in Figs. 4 and 5. As soon as they are past the edges of the table, the latch bolts spring inwardly beneath the table (Fig. 5) so that the table is supported by the flat upper surfaces 15 of the latch bolts. The locking lever 21 is then swung 180 in the opposite direction so as to move the locking pin 16 from the released position shown in Fig. 7 to the locked position shown in Fig. 8, thereby positively locking the table 3a in position between the carriers 7. It will be seen that table 3 or 3a fits snugly between the opposite spaced carriers 7, the end surfaces of the table engaging the side surfaces of the carriers to hold the table accurately in position. On the other hand, the table and carriers are free from any permanent interengaging projections which would interfere with the quick removal of one table and the quick pick up of a replacement table.

When the second table 3a has been connected to the carriers 7, as described, it is raised into position for the sheet-feeding device 4 and moved progressively upwardly under control of the mechanism 10a as the sheets are used up. When the stack is largely consumed and the table which carries it is sufiiciently raised, another table is positioned beneath it on the carrier rails 11 with a new stack of sheets which, after the current stack has been used up, is brought into operating position, the cycle being repeated in like manner.

The invention thus provides an extremely simple mechanism by means of which pre-stacking of the sheets supplied to a sheet-feeding mechanism can be easily and quickly effected. While a preferred form of the invention has been illustrated by way of example in the drawings and particularly described, it will be understood that the invention is in no way limited to this specific form and that suitable modifications may be made.

What I claim and desire to secure by Letters Patent is:

A reloading apparatus for sheet feeders comprising the combination of a plurality of like feed tables, a lifting and lowering mechanism for successively receiving and lifting the tables individually, said mechanism including a pair of toothed racks spaced apart a distance to receive a table between them for holding a stack of sheets thereon, a pair of connected pinions in driving engagement with each of said racks, a gear system driving said pinions to progressively raise the racks to continuously maintain the table in position for the top sheet of a stack of sheets to be in a predetermined position for taking by a sheet-taking device, a pair of opposite table carriers provided respectively on said racks spaced so as to releasably receive and support a table between them, said gear system being operable to selectively lower the racks to reload the sheet feeder with a second table having a new stack of sheets and normally after removal of an emptied table from the carriers upon exhausting the stack of sheets thereon, means actuated by said second table for automatically engaging said second table comprising latch bolts slidably supported by said carriers for longitudinal movement between a retracted and an extended position in which they engage said second table positioned between said carriers and means for biasing said bolts toward their extended position, said bolts having inclined surfaces engageable with said second table when said carriers are lowered and inclined in a direction to retract said bolts by said engagement, positive locking means on at least one of said carriers and means for quickly moving said locking means between a locked position in which it positively locks said table to said carriers and a released position.

References Cited in the file of this patent UNITED STATES PATENTS Great Britain July 22, 1948 

